*: add themis retry error check

remove go-themis circular dependency

kv/txn.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/juju/errors"
 	"github.com/ngaut/log"
+	"github.com/pingcap/go-themis"
 	"github.com/pingcap/tidb/terror"
 )
 
@@ -33,6 +34,7 @@ func IsRetryableError(err error) bool {
 	if terror.ErrorEqual(err, ErrRetryable) ||
 		terror.ErrorEqual(err, ErrLockConflict) ||
 		terror.ErrorEqual(err, ErrConditionNotMatch) ||
+		terror.ErrorEqual(err, themis.ErrRetryable) ||
 		// HBase exception message will tell you if you should retry or not
 		strings.Contains(err.Error(), "try again later") {
 		return true